As wireless communications technology has evolved, a variety of hardware and software solutions have been used to implement wireless networks. No clear standard for many of the design aspects of wireless systems now exists, and each of the differently designed networks has advantages and disadvantages. One of the variables in wireless networking is the wireless networking protocol used.
Global system for mobile communications (GSM, originally “Groupe de travail Spéciale pour les services Mobiles”) is a standard, or protocol, for digital cellular communications in the process of being adopted by over 60 countries. The GSM standard is currently used in the 900 MHz and 1800 MHz bands, and is typically used in wide area network applications. GSM, and other standards for wireless telephony, such as code division multiple access (CDMA), or “spread spectrum” include methods for handing a session off to a new coverage area, or cell, as the mobile device moves from cell to cell. Previous standards also have disadvantages, however. For example, the mobile telephony service may be unreliable or unavailable in certain areas. For those standards that use regulated regions of the radio frequency (RF) spectrum, rights to use the regulated regions of the spectrum must be obtained.
A personal communications network (PCN) is any network that supports personal communication services (PCS). The PCS are telecommunications services that bundle voice communications, numeric and text messaging, voice-mail and various other features into one device, service contract and bill. PCN does not share all of the limitations of traditional cellular telephony, and offers potentially wider application. For example, PCN offers wider bandwidth, or “broadband access”, and can provide greater availability with higher reliability than cellular in some geographic areas. In addition, PCN does not use a regulated area of the RF spectrum. PCN does use various wireless networking standards, such as Institute of Electronic and Electrical Engineering (IEEE) 802.11 and IEEE 802.11b, which use direct-sequence spread spectrum, and Bluetooth, which uses frequency-hopping spread spectrum. Ericsson initially developed Bluetooth as an inexpensive solution to unwiring devices, such as in an office environment. Bluetooth uses a special short-range radio frequency to communicate data between a Bluetooth transmitter and a Bluetooth receiver. Bluetooth, and similar standards used with PCN, currently lack the ability to adequately support movement of the host mobile device from one cell to another, and to adequately perform load balancing.
Details of the Bluetooth standard may be found at http://www.palowireless.com. Further details of the Bluetooth standard, and other wireless systems, may be found at:
“Specification of the Bluetooth System,” version 1.1: http://www.bluetooth.com/developer/specification/specification.asp;
IETF draft: “Temporally-Ordered Routing Algorithm (TORA) Version 1 Functional Specification”-http://www.ics.uci.edu/˜atm/adhoc/paper-collection/corson-draft-ietf-manet-tora-spec-00.txt;
Text: “Mobile Communications”, Jochen Schiller, Addison-Wesley, 2000;
Text: “Bluetooth—Connect Without Wires”, Bray & Sturman, Prentice Hall PTR, 2001;
Text: “Bluetooth Revealed”, Miller & Bisdikian, Prentice Hall PTR, 2001; and
Text: “Bluetooth Demystified”, Muller, McGraw-Hill, 2001.
An example of the failure of traditional Bluetooth networks to handle true mobility is the typical connection initiation process. Typically, in order to access a particular personal communication service (e.g., LAN Access Point, Phone, etc), the Bluetooth mobile device sends a request for service to all base station units (BSUs) within range, in the form of a standard Bluetooth command. In prior Bluetooth networks, the Bluetooth mobile device receives responses from every appropriately capable BSU within range, as well as from every other appropriately capable Bluetooth device within range. The Bluetooth mobile device must then choose to complete a connection to one of the responding BSUs, which is burdensome overhead for the mobile device. For example, every mobile device, or user, must examine data in every response, and make some load balancing decisions based on data from each of the responding BSUs.